1. Field of the Invention
The present invention relates to a method of manufacturing a composite material by melt-spraying to manufacture the composite material wherein either discontinuous fibers or both discontinuous fibers and grains form reinforcing constituents.
2. Background of the Invention
In a conventional method of manufacturing a composite material of such type, a preformed type is made by coating arranged continuous fibers with a melt-sprayed metal as the main constituent of the composite material and then forming the tape by hot pressing. In another conventional method of manufacturing a composite material of such type, a liner material is melt sprayed whose central portion consists of a reinforcing substance and whose peripheral portion is made of a metal as the main constituent of the composite material. In still another conventional method of manufacturing such a composite material, a preformed wire containing discontinuous fibers is melt-sprayed.
In the first mentioned conventional method above, the arranged continuous fiber are positioned in front of a melt sprayer including a melt-spray gun, and either the gun or continuous fibers are moved relative to the other to coat the fibers with the metal to create the preformed tape. A prescribed number of such preformed tapes are then piled together and hot pressed to increase their density or increase the tightness of the tapes at their boundary.
In the conventional method wherein a wire containing the discontinuous fibers is used, the wire is a preformed wire previously made as a composite substance or is a two-layer wire whose central portion includes the discontinuous fibers and whose peripheral portion is a metal forming the main constituent of the composite material. The wire is directly made as a composite material reinforced by the discontinuous fibers. Secondary processing such as high-temperature extrusion is performed in order not only to increase the density of the composite material and its tightness at the boundary between the metal and the discontinuous fibers but also to enhance the reliability of the material.
In the first mentioned conventional method above, the continuous fibers need to be arranged to an appropriate thickness and width so that a uniform metal coating layer can be formed around the fibers. For that reason, the speed of manufacture is very slow. Further, this method cannot be applied to discontinuous fibers because it is impossible to prevent the fibers from scattering.
In the other conventional method wherein discontinuous fibers are used, the fibers are subject to high temperature simultaneously with the melting of the metal because the reinforcing discontinuous fibers are passed through the melt-spray gun. For this reason, the fibers are damaged or molten and gather so that the effectiveness of reinforcement by the fibers is greatly reduced.